Enhanced synthesis of 3-hydroxypropionic acid by eliminating by-products using recombinant Escherichia coli as a whole cell biocatalyst

3-hydroxypropionic acid (3-HP) is a valuable platform chemical with high demand in the global market. Owing to its sustainability and environmental affability, the biosynthesis of 3-HP has gained a great deal of attention. The major challenges in biological production of 3-HP is by-product accumulation which significantly affects the titre and yield of 3-HP. In this work, efforts have been made to investigate the metabolic engineering of Escherichia coli to circumvent these constraints. From the mRNA expression studies, it was found that yqhD, poxB , and pta-ackA were the primary targets. The deletion of genes showed significant changes in the synthesis of 3-HP and other major metabolites such as propanediol and acetate. The deletion of yqhD significantly decreased the synthesis of propanediol and diverted the carbon flux towards 3-HP. Furthermore, the combined deletion of poxB and pta-ackA significantly showed the reduction of acetate concentration. The enhancement of 3-HP production has been attained by the combinatorial deletion of yqhD, poxB , and pta-ackA resulted the titre (440 mM vs. 556 mM) and yield (0.31 vs. 0.40). The present work could be an effective tool for the enhanced production of 3-HP with the reduced level of by-product accumulation.